The advent of technology providing mass-market access to the Internet places vast amounts of on-line information within relatively easy reach. The World Wide Web (WWW) (hereunder, the Web) underpins much of the growth of Internet use, particularly because of the ease of use, and also due to the intuitive user interface presented by Web browsers. Universal Resource Identifiers (URIs) are a ubiquitous addressing feature used to locate target resources in the Web context. This is particularly relevant when Web pages are used in conjunction with a Common Gateway Interface (CGI) scripting application, which allows the Web page to become, in essence, the front end of a myriad of databases accessible over the Internet.
Notwithstanding the explosive progress described however, a Web user is, in most cases, unable to “drill down” beyond a certain level of data, and must, in many cases, down-load an inconveniently large and cumbersome amount of information in order to locate useful information. Illustrating this fact, consider investigating all flights from London to Moscow departing from Heathrow airport on a given date. In order to make a selection based on a number of criteria such as departure time, airline, number of stops and so on, a long list of flights typically needs to be down-loaded and scanned, either manually or using a back-end application on a local personal computer (PC).
Further exemplifying the problem, certain types of data such as, for example, audio-visual (AV) data, typically manifest themselves as monolithic blocks of information. The internal structure of such data, whether it be a particular video segment, or fragment, in a movie, or a specific movement in a symphony, is neither visible, nor addressable, or consequently accessible in terms of fragments.
Taking a more extreme example, off-line audio-visual data, in the form of celluloid film archives, paper-based libraries, and a wealth of other sources, are also not addressable, and are thus invisible and inaccessible at the “fragment” level. Although particular books can be located, by call number and location in a library, specific chapters thereof are not visible or addressable, and consequently, not accessible.
Extensible Markup Language (XML) provides a drill down capability for a limited sub-set of on-line information, namely information which is coded in XML. The overwhelming bulk of available information has been produced in other programming formats such as Hypertext Markup Language (HTML), or alternatively, is in hard copy form in physical archives and libraries. The aforementioned types of information are referred to as “legacy” information.
Australian Patent No. 759681 discloses an approach referred to as AV addressing (being a shorthand way of referring to audio-visual addressing) for addressing audio-visual fragments by constructing a logical model for the class of audio-visual resources of interest. In accordance with the EBNF syntax convention adopted at [42], this addressing scheme is also referred to as the “mp” addressing scheme.
The logical model is used to form a hierarchical representation of the audio-visual resource including a representation of the audio-visual fragment of interest. A fragment identifier is used in an addressing scheme that is capable of addressing fragments of the audio-visual resource. Evaluating an audio-visual fragment identifier can be difficult, however, as the disclosed approach does not deal with well-defined tokens of a single media format. Instead the approach is concerned with multiple media formats and logical units that are conceptual rather than physical in nature. Furthermore, the semantics of the disclosed audio-visual addressing scheme can lead to very complex expressions which are difficult to resolve.